Hi Ernie,
Thanks for the information.
To clarify my 3rd question, I’d like to know where you shared this folder, SkyDrive Pro or SharePoint site? Meanwhile, since you said that most of the external users cannot see the files, does it mean user can access the folder, but cannot see the files under the folder?
Currently, for your situation, please let your external user click the link in the invitation email, and let the external user copy the URL of the folder and send the URL to you. after receiving the URL, please try to access it with the internal user permission and see if the issue persists. Normally, when we stop the inheritance between the folder and the files under it, we will not the see the files if we get the folder permission. In this case, could you please check whether the inheritance was stopped? If would be great if you can provide us with a screenshot of the error message from your external users.
Thanks,
Kevin Hu